Geographic and population disparities in cutaneous melanoma in the United States: state-level trends and national population-level analyses

BACKGROUND: Over recent decades, cutaneous melanoma (CM) incidence in the United States (US) has increased but now appears to be plateauing, whereas mortality has declined. However, much less is known about how CM incidence and mortality vary between states, or about how differences between states in incidence relate to lifestyle factors, ambient UV exposure, and prevention or health care resources. At the population level, most studies have compared overall CM incidence and mortality across broad racial and ethnic groups without describing age-specific or state-specific patterns. This lack of granularity limits our understanding of when and where different population groups bear the greatest CM burden and where targeted prevention and early detection efforts are most needed. METHODS: We conducted a cross-sectional study of the incidence and mortality trends of CM in the US from 2001 to 2019, including state-level analyses of temporal trends and ecological correlates, as well as national population-level analyses by age, sex, and race/ethnicity. Annual percent change (APC) and average annual percent change (AAPC) were calculated, and ecological correlations and multivariable linear regression models were fitted with state-level AAPC in CM incidence as the outcome. RESULTS: Between 2001 and 2016, CM incidence increased significantly (APC, 1.95% [95% CI, 1.67% to 2.24%], p < 0.001) and then stabilized from 2016 to 2019 (APC, -0.59% [95% CI, -3.36% to 2.27%], p = 0.662). During the study period, mortality declined significantly (AAPC, -1.52% [95% CI, -2.38% to -0.66%], p < 0.001). A persistent upward incidence trend was observed in 24 states, predominantly in the Midwest and Southern regions. The incidence rate ratio (IRR) between the highest- and lowest-rate states increased from 2.63 in 2001 to 4.85 in 2019, whereas the mortality rate ratio (MRR) narrowed to 1.19 by 2019. In ecological analyses, higher state-level obesity prevalence and lower physical activity level were each associated with higher AAPC in CM incidence, whereas higher personal doctor rates were inversely associated. Average daily solar insolation and tanning/sunscreen policies were not significantly related to the AAPC. Across all racial/ethnic groups, CM incidence was higher in young women than in young men, with sex-specific crossover ages varying by race/ethnicity, while young men consistently experienced higher mortality. Age-stratified analyses showed that disparities in CM incidence and mortality rates between non-Hispanic Whites and other races/ethnicities were more pronounced in young individuals than in the elderly. There was also substantial interstate variation in incidence rate ratios comparing non-Hispanic Whites with other racial/ethnic groups. CONCLUSIONS: Despite overall plateauing incidence and declining mortality, CM remains highly unequal across states and population groups. Interstate incidence disparities widened over time, with marked variation by age, sex, and race/ethnicity. These findings provide a more detailed picture of geographic and population-level disparities in CM and may help inform future surveillance, risk stratification, and hypothesis-driven prevention research.